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  Subjects -> VETERINARY SCIENCE (Total: 216 journals)
Showing 1 - 63 of 63 Journals sorted alphabetically
Acta Scientiae Veterinariae     Open Access   (Followers: 1)
Acta Veterinaria     Open Access   (Followers: 1)
Acta Veterinaria Brasilica     Open Access  
Acta Veterinaria Hungarica     Full-text available via subscription   (Followers: 2)
Acta Veterinaria Scandinavica     Open Access   (Followers: 1)
Advances in Animal Biosciences     Full-text available via subscription   (Followers: 9)
Advances in Small Animal Medicine and Surgery     Hybrid Journal  
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 12)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 12)
African Journal of Wildlife Research     Full-text available via subscription   (Followers: 1)
Alexandria Journal of Veterinary Sciences     Open Access  
American Journal of Animal and Veterinary Sciences     Open Access   (Followers: 8)
American Journal of Primatology     Hybrid Journal   (Followers: 10)
American Journal of Veterinary Research     Full-text available via subscription   (Followers: 21)
Anatomia, Histologia, Embryologia: Journal of Veterinary Medicine Series C     Hybrid Journal   (Followers: 3)
Animal Behaviour     Hybrid Journal   (Followers: 99)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 5)
Animal Health Research Reviews     Hybrid Journal   (Followers: 3)
Animal Nutrition     Open Access   (Followers: 7)
Animal Reproduction     Open Access  
Animal Reproduction Science     Hybrid Journal   (Followers: 4)
Animals     Open Access   (Followers: 6)
Annals of Agricultural and Environmental Medicine     Open Access   (Followers: 1)
Annual Review of Animal Biosciences     Full-text available via subscription   (Followers: 4)
Anthrozoos : A Multidisciplinary Journal of The Interactions of People & Animals     Hybrid Journal   (Followers: 6)
Archives of Animal Nutrition     Hybrid Journal   (Followers: 6)
Archivos de Medicina Veterinaria     Open Access   (Followers: 1)
Arquivo Brasileiro de Medicina Veterinária e Zootecnia     Open Access  
Arquivos de Ciências Veterinárias e Zoologia da UNIPAR     Open Access  
Ars Veterinaria     Open Access  
Asian Journal of Medical and Biological Research     Open Access  
Asian Journal of Poultry Science     Open Access   (Followers: 3)
Atatürk Üniversitesi Veteriner Bilimleri Dergisi     Open Access  
Australian Equine Veterinarian     Full-text available via subscription   (Followers: 3)
Australian Veterinary Journal     Hybrid Journal   (Followers: 15)
Avances en Ciencias Veterinarias     Open Access  
Avian Diseases     Full-text available via subscription   (Followers: 3)
Avian Diseases Digest     Full-text available via subscription   (Followers: 2)
Avian Pathology     Hybrid Journal   (Followers: 2)
Bangladesh Journal of Animal Science     Open Access  
Bangladesh Journal of Veterinary Medicine     Open Access   (Followers: 1)
Bangladesh Veterinarian     Open Access  
BMC Veterinary Research     Open Access   (Followers: 10)
Brazilian Journal of Veterinary Research and Animal Science     Open Access   (Followers: 8)
Buletin Peternakan : Bulletin of Animal Science     Full-text available via subscription  
Buletin Veteriner Udayana     Open Access  
Bulletin of Animal Health and Production in Africa     Full-text available via subscription   (Followers: 1)
Bulletin of the Veterinary Institute in Pulawy     Open Access  
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca : Food Science and Technology     Open Access  
Canadian Journal of Veterinary Research     Full-text available via subscription   (Followers: 8)
Case Reports in Veterinary Medicine     Open Access   (Followers: 5)
Ciência Animal Brasileira     Open Access  
Ciência Rural     Open Access  
Cogent Food & Agriculture     Open Access  
Companion Animal     Full-text available via subscription   (Followers: 8)
Domestic Animal Endocrinology     Hybrid Journal   (Followers: 4)
Equine Health     Full-text available via subscription   (Followers: 3)
Equine Veterinary Education     Hybrid Journal   (Followers: 9)
Equine Veterinary Journal     Hybrid Journal   (Followers: 13)
Ethiopian Veterinary Journal     Open Access   (Followers: 4)
Eurasian Journal of Veterinary Sciences     Open Access   (Followers: 1)
FAVE Sección Ciencias Veterinarias     Open Access  
Frontiers in Veterinary Science     Open Access   (Followers: 1)
Global Journal of Animal Scientific Research     Open Access   (Followers: 1)
Human & Veterinary Medicine - International Journal of the Bioflux Society     Open Access   (Followers: 5)
ILAR Journal     Hybrid Journal  
In Practice     Full-text available via subscription   (Followers: 2)
Indian Journal of Animal Sciences     Open Access   (Followers: 4)
Indian Journal of Veterinary Anatomy     Full-text available via subscription   (Followers: 3)
Indonesia Medicus Veterinus     Open Access  
Intas Polivet     Full-text available via subscription  
International Journal for Agro Veterinary and Medical Sciences     Open Access   (Followers: 2)
International Journal of Livestock Research     Open Access  
International Journal of Veterinary Science and Medicine     Open Access   (Followers: 4)
Iranian Journal of Applied Animal Science     Open Access  
Irish Veterinary Journal     Open Access   (Followers: 5)
İstanbul Üniversitesi Veteriner Fakültesi Dergisi     Open Access  
Journal of Veterinary Science & Technology     Open Access   (Followers: 6)
Journal of Advanced Veterinary and Animal Research     Open Access   (Followers: 5)
Journal of Animal Behaviour and Biometeorology     Open Access   (Followers: 1)
Journal of Animal Physiology and Animal Nutrition     Hybrid Journal   (Followers: 5)
Journal of Animal Science and Technology     Open Access  
Journal of Applied Animal Nutrition     Hybrid Journal   (Followers: 3)
Journal of Avian Medicine and Surgery     Full-text available via subscription   (Followers: 5)
Journal of Buffalo Science     Hybrid Journal  
Journal of Equine Veterinary Science     Hybrid Journal   (Followers: 11)
Journal of Exotic Pet Medicine     Full-text available via subscription   (Followers: 3)
Journal of Experimental and Applied Animal Sciences     Open Access  
Journal of Feline Medicine & Surgery     Hybrid Journal   (Followers: 4)
Journal of Research in Forestry, Wildlife and Environment     Open Access   (Followers: 3)
Journal of Small Animal Practice     Hybrid Journal   (Followers: 11)
Journal of the American Veterinary Medical Association     Full-text available via subscription   (Followers: 27)
Journal of the Selva Andina Research Society     Open Access  
Journal of the South African Veterinary Association     Open Access   (Followers: 2)
Journal of Venomous Animals and Toxins     Open Access   (Followers: 4)
Journal of Veterinary Advances     Open Access   (Followers: 4)
Journal of Veterinary Behavior: Clinical Applications and Research     Hybrid Journal   (Followers: 4)
Journal of Veterinary Cardiology     Full-text available via subscription   (Followers: 7)
Journal of Veterinary Diagnostic Investigation     Hybrid Journal   (Followers: 8)
Journal of Veterinary Emergency and Critical Care     Hybrid Journal   (Followers: 15)
Journal of Veterinary Internal Medicine     Open Access   (Followers: 19)
Journal of Veterinary Medical Education     Partially Free   (Followers: 11)
Journal of Veterinary Medicine     Open Access   (Followers: 8)
Journal of Veterinary Medicine and Animal Health     Open Access   (Followers: 4)
Journal of Veterinary Pharmacology and Therapeutics     Hybrid Journal   (Followers: 8)
Journal of Veterinary Science & Medical Diagnosis     Hybrid Journal   (Followers: 4)
Journal of Zoo and Aquarium Research     Open Access   (Followers: 2)
Journal of Zoo and Wildlife Medicine     Full-text available via subscription   (Followers: 5)
Jurnal Agripet     Open Access  
Kenya Veterinarian     Full-text available via subscription   (Followers: 2)
kleintier konkret     Hybrid Journal  
Livestock     Full-text available via subscription   (Followers: 1)
Macedonian Veterinary Review     Open Access   (Followers: 2)
MEDIA PETERNAKAN - Journal of Animal Science and Technology     Open Access   (Followers: 1)
Medical Mycology     Open Access   (Followers: 3)
Medical Mycology Case Reports     Open Access  
Microbes and Health     Open Access   (Followers: 1)
New Zealand Veterinary Journal     Full-text available via subscription   (Followers: 11)
New Zealand Veterinary Nurse     Full-text available via subscription   (Followers: 3)
Nigerian Veterinary Journal     Open Access  
Nutrición Animal Tropical     Open Access   (Followers: 1)
Onderstepoort Journal of Veterinary Research     Open Access   (Followers: 3)
Open Access Animal Physiology     Open Access   (Followers: 4)
Open Journal of Animal Sciences     Open Access   (Followers: 4)
Open Journal of Veterinary Medicine     Open Access   (Followers: 4)
Pesquisa Veterinária Brasileira     Open Access  
pferde spiegel     Hybrid Journal  
Philippine Journal of Veterinary Medicine     Full-text available via subscription  
Polish Journal of Veterinary Sciences     Open Access   (Followers: 3)
Pratique Médicale et Chirurgicale de l'Animal de Compagnie     Full-text available via subscription  
Preventive Veterinary Medicine     Hybrid Journal   (Followers: 10)
REDVET. Revista Electrónica de Veterinaria     Open Access  
Reproduction in Domestic Animals     Hybrid Journal   (Followers: 1)
Research & Reviews : Journal of Veterinary Science and Technology     Full-text available via subscription   (Followers: 1)
Research in Veterinary Science     Hybrid Journal   (Followers: 10)
Research Journal of Veterinary Sciences     Open Access   (Followers: 8)
Revista Brasileira de Ciência Veterinária     Open Access  
Revista Brasileira de Higiene e Sanidade Animal     Open Access  
Revista Brasileira de Parasitologia Veterinaria     Open Access  
Revista Brasileira de Reprodução Animal     Open Access  
Revista Brasileira de Zootecnia     Open Access   (Followers: 2)
Revista Ciencia Animal     Open Access  
Revista Ciencias Veterinarias     Open Access  
Revista Científica     Open Access  
Revista Colombiana de Ciencias Pecuarias (Colombian journal of animal science and veterinary medicine)     Open Access   (Followers: 1)
Revista Complutense de Ciencias Veterinarias     Open Access  
Revista da Sociedade Brasileira de Ciência em Animais de Laboratório     Open Access  
Revista de Ciências Agroveterinárias     Open Access  
Revista de Educação Continuada em Medicina Veterinária e Zootecnia     Open Access  
Revista de Investigaciones Veterinarias del Perú     Open Access  
Revista de la Facultad de Medicina Veterinaria y de Zootecnia     Open Access   (Followers: 1)
Revista de Medicina Veterinaria     Open Access  
Revista de Salud Animal     Open Access  
Revista Mexicana de Ciencias Pecuarias     Open Access  
Revista MVZ Córdoba     Open Access  
Revista Veterinaria     Open Access  
Revue Marocaine des Sciences Agronomiques et Vétérinaires     Open Access  
SA Stud Breeder / SA Stoetteler     Full-text available via subscription  
Schweizer Archiv für Tierheilkunde     Hybrid Journal  
Science and Animal Health     Open Access  
Scientific Journal of Animal Science     Open Access   (Followers: 3)
Scientific Journal of Veterinary Advances     Open Access   (Followers: 1)
Small Ruminant Research     Hybrid Journal   (Followers: 2)
Sokoto Journal of Veterinary Sciences     Open Access   (Followers: 1)
Spei Domus     Open Access  
Tanzania Veterinary Journal     Full-text available via subscription   (Followers: 1)
team.konkret     Open Access  
The Dairy Mail     Full-text available via subscription   (Followers: 3)
Theriogenology     Hybrid Journal   (Followers: 1)
Topics in Companion Animal Medicine     Hybrid Journal   (Followers: 3)
Transboundary and Emerging Diseases     Hybrid Journal   (Followers: 2)
Trends in Animal and Veterinary Sciences     Open Access   (Followers: 5)
Trends in Parasitology     Full-text available via subscription   (Followers: 9)
Tropical Animal Health and Production     Hybrid Journal  
Tropical Veterinarian     Full-text available via subscription   (Followers: 1)
Turkish Journal of Veterinary and Animal Sciences     Open Access  
veterinär spiegel     Hybrid Journal   (Followers: 1)
Veterinária e Zootecnia     Open Access  
Veterinária em Foco     Open Access  
Veterinaria México     Open Access  
Veterinária Notícias     Open Access  
Veterinary Anaesthesia and Analgesia     Hybrid Journal   (Followers: 11)
Veterinary and Comparative Oncology     Hybrid Journal   (Followers: 7)
Veterinary Clinical Pathology     Hybrid Journal   (Followers: 9)
Veterinary Clinics of North America: Equine Practice     Full-text available via subscription   (Followers: 9)
Veterinary Clinics of North America: Exotic Animal Practice     Full-text available via subscription   (Followers: 7)
Veterinary Clinics of North America: Food Animal Practice     Full-text available via subscription   (Followers: 5)
Veterinary Clinics of North America: Small Animal Practice     Full-text available via subscription   (Followers: 15)
Veterinary Dermatology     Hybrid Journal   (Followers: 7)
Veterinary Immunology and Immunopathology     Hybrid Journal   (Followers: 9)
Veterinary Journal     Hybrid Journal   (Followers: 15)
Veterinary Medicine and Animal Sciences     Open Access   (Followers: 3)
Veterinary Medicine and Science     Open Access  
Veterinary Medicine International     Open Access   (Followers: 7)
Veterinary Medicine: Research and Reports     Open Access   (Followers: 4)
Veterinary Microbiology     Hybrid Journal   (Followers: 8)
Veterinary Nurse     Full-text available via subscription   (Followers: 3)
Veterinary Nursing Journal     Hybrid Journal   (Followers: 3)
Veterinary Ophthalmology     Hybrid Journal   (Followers: 6)
Veterinary Parasitology     Hybrid Journal   (Followers: 9)

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Journal Cover Veterinary Microbiology
  [SJR: 1.425]   [H-I: 84]   [8 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0378-1135 - ISSN (Online) 1873-2542
   Published by Elsevier Homepage  [2817 journals]
  • Antimicrobial susceptibility of Mycoplasma bovis isolates from veal calves
           and dairy cattle in the Netherlands
    • Abstract: Publication date: 30 June 2016
      Source:Veterinary Microbiology, Volume 189
      Author(s): Annet Heuvelink, Constance Reugebrink, Jet Mars
      Control of Mycoplasma bovis infections depends on good husbandry practices and antibiotic treatment. To allow more prudent use of antimicrobial drugs, there is a need for information on the susceptibility profile of this pathogen. The objective of the present study was to analyse the in vitro antimicrobial susceptibility of clinical M. bovis isolates in the Netherlands. The collection comprised 95 bovine isolates, originating from lungs (n=56), mastitis milk (n =27), and synovial fluid (n =12), collected between 2008 and 2014. Minimal inhibitory concentrations (MICs) were assessed by broth microdilution, both by using in-house prepared MIC plates and by using commercially available MIC plates. For each antimicrobial agent, the range of MIC results, the MIC50, and MIC90 values were calculated. M. bovis strains recently isolated in the Netherlands appeared to be characterized by relatively high MIC values for antimicrobial agents that, until now, have been recommended by the Dutch Association of Veterinarians for treating pneumonia caused by Mycoplasma species. Fluoroquinolones appeared to be the most efficacious in inhibiting M. bovis growth, followed by tulathromycin and oxytetracycline. The highest MIC values were obtained for erythromycin, tilmicosin, and tylosin. Future studies should be done on determining M. bovis specific clinical breakpoints, standardization of methods to determine MIC values as well as molecular studies on detection of antimicrobial resistance mechanisms of M. bovis isolates to develop PCR assays for determining resistance.

      PubDate: 2016-04-27T14:16:54Z
  • Aerosol transmission of foot-and-mouth disease virus Asia-1 under
           experimental conditions
    • Abstract: Publication date: Available online 26 April 2016
      Source:Veterinary Microbiology
      Author(s): C. Colenutt, J.L. Gonzales, D.J. Paton, J. Gloster, N. Nelson, C. Sanders
      Foot-and-mouth disease virus (FMDV) control measures rely on understanding of virus transmission mechanisms. Direct contact between naïve and infected animals or spread by contaminated fomites is prevented by quarantines and rigorous decontamination procedures during outbreaks. Transmission of FMDV by aerosol may not be prevented by these control measures and this route of transmission may allow infection of animals at distance from the infection source. Understanding the potential for aerosol spread of specific FMDV strains is important for informing control strategies in an outbreak. Here, the potential for transmission of an FMDV Asia 1 strain between pigs and cattle by indirect aerosol exposure was evaluated in an experimental setting. Four naïve calves were exposed to aerosols emitted from three infected pigs in an adjacent room for a 10h period. Direct contact between pigs and cattle and fomite transfer between rooms was prevented. Viral titres in aerosols emitted by the infected pigs were measured to estimate the dose that calves were exposed to. One of the calves developed clinical signs of FMD, whilst there was serological evidence for spread to cattle by aerosol transmission in the remaining three calves. This highlights the possibility that this FMDV Asia 1 strain could be spread by aerosol transmission given appropriate environmental conditions should an outbreak occur in pigs. Our estimates suggest the exposure dose required for aerosol transmission was higher than has been previously quantified for other serotypes, implying that aerosols are less likely to play a significant role in transmission and spread of this FMDV strain.

      PubDate: 2016-04-27T14:16:54Z
  • Characterization of canine and feline methicillin-resistant Staphylococcus
           pseudintermedius (MRSP) from Thailand
    • Abstract: Publication date: Available online 25 April 2016
      Source:Veterinary Microbiology
      Author(s): Kristina Kadlec, Sonja Weiß, Sarah Wendlandt, Stefan Schwarz, Walaiporn Tonpitak
      Methicillin-resistant Staphylococcus pseudintermedius (MRSP) in small animal practice are very difficult to treat due to multi-resistance. In contrast to other countries, little is known about MRSP from Thailand. In particular, information on feline MRSP isolates in general is rare. In total, 39 MRSP isolates from dogs (n=28) and cats (n=11) from Thailand collected from independent clinical cases were used. Oxacillin resistance and presence of the mecA gene was confirmed. Susceptibility to additional 29 antimicrobial agents was tested according to CLSI recommendations. Antimicrobial resistance genes were detected by PCR assays. Molecular typing comprised spa typing, dru typing and macrorestriction analysis with subsequent pulsed-field gel electrophoresis (PFGE). For selected isolates, multi-locus sequence typing (MLST) was performed. All isolates were multi-resistant with resistance to at least six classes of antimicrobial agents. In all cases corresponding resistance genes were detected. In addition to mecA, the genes blaZ, cat pC221, aacA/aphD, erm(B), dfrG, tet(M) and tet(K) were identified. Six spa types (t02, t05, t09, t10, t23, t72), eleven dru types (dt8ak, dt10ao, dt10cp, dt10cq, dt11a, dt11bo, dt11cb, dt11cj, dt11v, dt11y, dt11z) and 27 PFGE types (designated as A1-A10, B1-B8, C1-C2, D, E, F, G, H, I, J) were identified. MLST for one isolate of each main PFGE pattern A-J revealed seven types [ST45 (n=3), ST112, ST155, ST282 and the novel types ST432, ST433 (n=2) and ST434]. This study showed that MRSP isolates from clinical cases in individual dogs and cats in Thailand are multi-resistant with similar resistance genes and characteristics as isolates from Europe and North America.

      PubDate: 2016-04-27T14:16:54Z
  • Antimicrobial resistance and class 1 integron-associated gene cassettes in
           Salmonella enterica serovar Typhimurium isolated from pigs at slaughter
           and abattoir environment
    • Abstract: Publication date: Available online 25 April 2016
      Source:Veterinary Microbiology
      Author(s): Graciela Volz Lopes, Geovana Brenner Michael, Marisa Cardoso, Stefan Schwarz
      Forty-five multi-resistant Salmonella enterica subsp. enterica serovar (S.) Typhimurium isolates obtained at five pig abattoirs in Southern Brazil were characterized. Their relatedness was determined by XbaI-macrorestriction analysis. Resistance genes, integrons and plasmid-mediated quinolone resistance genes (PMQR) were investigated by PCR. Amplicons for the variable part of class 1 integrons and the quinolone resistance-determining regions (QRDR) were sequenced. Plasmids were characterized by conjugation assays and replicon typing. Eighteen XbaI-macrorestriction patterns and 19 plasmid profiles were seen. Resistance to ampicillin (bla TEM), chloramphenicol (catA1 and floR), streptomycin (strA-strB), streptomycin/spectinomycin (aadA variant), sulphonamides (sul1, sul2, sul3) and tetracyclines [tet(A) and tet(B)] were commonly found. A trimethoprim resistance gene, dfrA8, was identified on a 100-kb plasmid. Single substitutions in the QRDR of GyrA but no PMQR genes were found. Twenty-five isolates carried class 1 integrons with an aadA23 gene cassette or unusual class 1 integrons with a dfrA12-orfF-aadA27 gene cassette array. Both integrons were found on large conjugative plasmids. Salmonella plasmid-located virulence genes spvR, spvA, spvB, rck and pefA were found on an IncFIB resistance plasmid. Hybrid virulence-resistance plasmids or plasmids harbouring class 1 integrons may play a role in the maintenance and dissemination of antimicrobial resistance among S. Typhimurium in this pig production system.

      PubDate: 2016-04-27T14:16:54Z
  • Low pathogenic avian influenza (H9N2) in chicken: Evaluation of an
           ancestral H9-MVA vaccine
    • Abstract: Publication date: Available online 26 April 2016
      Source:Veterinary Microbiology
      Author(s): Mariette F. Ducatez, Jens Becker, Astrid Freudenstein, Maxence Delverdier, Mattias Delpont, Gerd Sutter, Jean-Luc Guérin, Asisa Volz
      Modified Vaccinia Ankara (MVA) has proven its efficacy as a recombinant vector vaccine for numerous pathogens including influenza virus. The present study aimed at evaluating a recombinant MVA candidate vaccine against low pathogenic avian influenza virus subtype H9N2 in the chicken model. As the high genetic and antigenic diversity of H9N2 viruses increases vaccine design complexity, one strategy to widen the range of vaccine coverage is to use an ancestor sequence. We therefore generated a recombinant MVA encoding for the gene sequence of an ancestral hemagglutinin H9 protein (a computationally derived amino acid sequence of the node of the H9N2 G1 lineage strains was obtained using the ANCESCON program). We analyzed the genetics and the growth properties of the MVA vector virus confirming suitability for use under biosafety level 1 and tested its efficacy when applied either as an intra-muscular (IM) or an oral vaccine in specific pathogen free chickens challenged with A/chicken/Tunisia/12/2010(H9N2). Two control groups were studied in parallel (unvaccinated and inoculated birds; unvaccinated and non-inoculated birds). IM vaccinated birds seroconverted as early as four days post vaccination and neutralizing antibodies were detected against A/chicken/Tunisia/12/2010(H9N2) in all the birds before challenge. The role of local mucosal immunity is unclear here as no antibodies were detected in eye drop or aerosol vaccinated birds. Clinical signs were not detected in any of the infected birds even in absence of vaccination. Virus replication was observed in both vaccinated and unvaccinated chickens, suggesting the MVA-ancestral H9 vaccine may not stop virus spread in the field. However vaccinated birds showed less histological damage, fewer influenza-positive cells and shorter virus shedding than their unvaccinated counterparts.

      PubDate: 2016-04-27T14:16:54Z
  • The serine protease autotransporter Tsh contributes to the virulence of
           Edwardsiella tarda
    • Abstract: Publication date: Available online 25 April 2016
      Source:Veterinary Microbiology
      Author(s): Yong-hua Hu, Hai-zhen Zhou, Qian-wen Jin, Jian Zhang
      The temperature-sensitive hemagglutinin (Tsh), identified as serine protease autotransporters of the Enterobacteriaceae (SPATEs) proteins, is an important virulence factor for avian-pathogenic Escherichia coli (APEC) and uropathogenic E. coli. However, little is known about the role of Tsh as a virulence factor in Edwardsiella tarda, a severe fish pathogen. In this study, we characterized the Tsh of E. tarda (named TshEt) and examined its function and vaccine potential. TshEt is composed of 1,224 residues and has three functional domains typical for autotransporters. Quantitative real-time reverse transcriptase-PCR analysis showed that expression of tshEt was upregulated under conditions of high temperature, increased cell density, high pH, and iron starvation and during the infection of host cells. A markerless tsh in-frame mutant strain, TX01Δtsh, was constructed to determine whether TshEt participates in the pathogenicity of E. tarda, Compared to the wild type TX01, TX01Δtsh exhibited (i) retarded biofilm growth, (ii) decreased resistance against serum killing, (iii) impaired ability to block the host immune response, (iv) attenuated tissue and cellular infectivity. Introduction of a trans-expressed tsh gene restored the lost virulence of TX01Δtsh. The passenger domain of TshEt contains a putative serine protease (PepS) that exhibits apparent proteolytic activity when expressed in and purified from E. coli as a recombinant protein (rPepS). When used as a subunit vaccine to immunize Japanese flounder, rPepS was able to induce effective immune protection. This is the first study of Tsh in a fish pathogen, and the results suggest that TshEt exerts pleiotropic effects on the pathogenesis of E. tarda.

      PubDate: 2016-04-27T14:16:54Z
  • Genome-wide mining of potential virulence-associated genes in Riemerella
           anatipestifer using random transposon mutagenesis
    • Abstract: Publication date: Available online 26 April 2016
      Source:Veterinary Microbiology
      Author(s): Xintao Ni, Pan Jiang, Linlin Xing, Changcan Ou, Hui Yu, Jingjing Qi, Bingqing Sun, Junsheng Cui, Guijun Wang, Qinghai Hu
      Riemerella anatipestifer infection is a severe disease confronting the duck industry worldwide. However, little is known about the molecular basis of R. anatipestifer pathogenesis. In this study, we screened 3580 transposon Tn4351 insertion mutagenesis mutants of the highly virulent strain YZb1 in a duckling infection experiment and found 29 of them to be attenuated and 28 potential virulence-associated genes were identified. Molecular characterization of transposon insertion sites showed that of the 28 screened genes, two were predicted to encode TonB-dependent outer membrane receptor (plugs), sixteen encoded enzymes, and seven encoded hypothetical proteins. In addition, of the 28 affected genes, 19 were only found in bacteria belonging to the phylum Bacteroidetes and 10 were only found in the family Flavobacteriaceae. The median lethal dose of the mutants M11 and M29, which was affected in Riean_0060 and Riean_1537 respectively, were about 1700-fold and 210-fold higher than that of the wild-type strain YZb1, and those of the complemented strains M11(pRES-Riean_0060) and M29(pRES-Riean_1537) were decreased by 25- and 3-fold respectively compared to those of the mutants M11 and M29. Additional analysis indicated that the blood bacterial loading of ducklings infected with M11 or M29 was decreased significantly, as compared with that in ducklings infected with the wild-type strain YZb1. Thus, our results indicate that Riean_0060 and Riean_1537 were involved in R. anatipestifer pathogenesis.

      PubDate: 2016-04-27T14:16:54Z
  • Evolution of equine infectious anaemia in naturally infected mules with
           different serological reactivity patterns prior and after immune
    • Abstract: Publication date: 30 June 2016
      Source:Veterinary Microbiology, Volume 189
      Author(s): Gian Luca Autorino, Claudia Eleni, Giuseppe Manna, Raffaele Frontoso, Roberto Nardini, Cristiano Cocumelli, Francesca Rosone, Andrea Caprioli, Lavinia Alfieri, Maria Teresa Scicluna
      Information on equine infectious anaemia (EIA) in mules, including those with an equivocal reaction in agar gel immunodiffusion test (AGIDT), is scarce. For this, a study was conducted to evaluate the clinical, viral loads and pathological findings of two groups of naturally infected asymptomatic mules, respectively with a negative/equivocal and positive AGIDT reactivity, which were subjected to pharmacological immune suppression (IS). A non-infected control was included in the study that remained negative during the observation period. Throughout the whole study, even repeated episodes of recrudescence of EIA were observed in 9 infected mules, independently from their AGIDT reactivity. These events were generally characterised by mild, transient alterations, typical of the EIA acute form represented by hyperthermia and thrombocytopenia, in concomitance with viral RNA (vRNA) peaks that were higher in the Post-IS period, reaching values similar to those of horses during the clinical acute phase of EIA. Total tissue viral nucleic acid loads were greatest in animals with the major vRNA activity and in particular in those with negative/equivocal AGIDT reactivity. vRNA replication levels were around 10–1000 times lower than those reported in horses, with the animals still presenting typical alterations of EIA reactivation. Macroscopic lesions were absent in all the infected animals while histological alterations were characterised by lymphomonocyte infiltrates and moderate hemosiderosis in the cytoplasm of macrophages. On the basis of the above results, even mules with an equivocal/negative AGIDT reaction may act as EIAV reservoirs. Moreover, such animals could escape detection due to the low AGIDT sensitivity and therefore contribute to the maintenance and spread of the infection.

      PubDate: 2016-04-27T14:16:54Z
  • Colonization with methicillin-resistant Staphylococcus pseudintermedius in
           multi-dog households: A longitudinal study using whole genome sequencing
    • Abstract: Publication date: 30 June 2016
      Source:Veterinary Microbiology, Volume 189
      Author(s): Ulrika Windahl, Joakim Ågren, Bodil S. Holst, Stefan Börjesson
      Despite a worldwide increase in the presence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs and its potential to cause serious canine health problem, the understanding of the transmission and long-term carriage of MRSP is limited. The objective of this study was to investigate the transmission of MRSP to contact dogs living in multiple dog households where one or more of the dogs had been diagnosed with a clinically apparent infection with MRSP. MRSP carriage was investigated over several months in 11 dogs living in four separate multiple dog households where an MRSP infection in a dog had been diagnosed. Whole-genome sequencing was used for genotypic characterization. Contact dogs were only MRSP-positive if the index dog was positive on the same sample occasion. Three contact dogs were consistently MRSP-negative. The data from whole genome sequencing showed similarities between isolates within each family group, indicating that MRSP was transmitted within each family. The results show that the risk of MRSP-colonization in dogs living with an MRSP-infected dog is reduced if the index dog becomes MRSP negative. All of the contact dogs will not carry MRSP continuously during the time the index dog is MRSP-positive. The information yielded from whole genome sequencing showed the methodology to be a promising additional tool in epidemiologic investigations of MRSP transmission.

      PubDate: 2016-04-27T14:16:54Z
  • The first experimental research on the pathogenicity of Arcobacter
           butzleri in zebrafish
    • Abstract: Publication date: Available online 22 April 2016
      Source:Veterinary Microbiology
      Author(s): Mehmet Nuri Açik, Hayati Yüksel, Aykut Ulucan, Burhan Çetinkaya
      This experimental study was conducted to investigate the pathogenicity and histopathology of Arcobacter butzleri in zebrafish model organism. Firstly, mean infective dose (ID50) of A. butzleri was calculated in zebrafish as 1.3×108 CFU/mL and 1×105 CFU/mL by immersion and intraperitoneal injection, respectively. For histopathological trials, the ID50 of A. butzleri were given to zebrafish by both immersion and intraperitoneal routes and then, clinical and pathological findings were evaluated on days 1, 3, 5, 7 and 21 of the experiment. During the experimental period, no clinical signs or gross lesions of disease were observed in the zebrafish groups infected with the ID50 of A. butzleri by either method. In the histopathological examination, acute inflammation characterized by neutrophil and plasma cells and local necrosis or congestion were determined in liver, kidney, spleen, gaster and other visceral organs. In addition peritonitis, leukocyte infiltration, villous atrophy and septicemia were observed in the experimental groups. Neither gross nor microscopic lesions were detected in the control groups. This study presented the first report of experimental A. butzleri infection in wild zebrafish. In the light of the findings obtained here, it was concluded that zebrafish could be used as a model organism to investigate pathogenicity and histopathology of arcobacters.

      PubDate: 2016-04-23T13:54:59Z
  • Lineage associated expression of virulence traits in bovine-adapted
           Staphylococcus aureus
    • Abstract: Publication date: Available online 21 April 2016
      Source:Veterinary Microbiology
      Author(s): Kathleen E. Budd, Jennifer Mitchell, Orla M. Keane
      Bovine mastitis is the most costly disease to the dairy industry worldwide with Staphylococcus aureus commonly associated with intramammary infections that are persistent and refractory to treatment. The strains of S. aureus that cause mastitis predominantly belong to a number of well-described bovine-adapted lineages. The objective of this study was to determine if a variety of potential virulence traits were associated with lineage. Bovine-adapted S. aureus isolates (n=120), belonging to lineages CC97, CC151 and ST136, were tested for their ability to adhere to and internalise within cultured bovine mammary epithelial cells (bMEC), to bind bovine fibronectin, to form a biofilm in TSB, TSB+1% glucose and TSB+4% NaCl, and to induce an immune response from bMEC. There were no significant differences between the lineages in ability to adhere to or internalise within bMEC although there were significant differences between individual isolates. For lineages CC97 and ST136, mammalian cell adherence was correlated with the ability to bind bovine fibronectin, however isolates from CC151 could not bind bovine fibronectin in vitro, but adhered to bMEC in a fibronectin-independent manner. There were significant differences between the lineages in ability to form a biofilm in all three growth media with ST136 forming the strongest biofilm while CC151 formed the weakest biofilm. Lineages also differed in their ability to elicit an immune response from bMEC with CC97 eliciting a stronger immune response than CC151 and ST136. These data indicate the potential for both lineage and strain-specific virulence and a strain-specific response to infection in vivo and caution against extrapolating an effect from a single strain of S. aureus to draw conclusions regarding virulence or the host response to infection in unrelated lineages.

      PubDate: 2016-04-23T13:54:59Z
  • Determining the optimal number of individual samples to pool for
           quantification of average herd levels of antimicrobial resistance genes in
           Danish pig herds using high-throughput qPCR
    • Abstract: Publication date: Available online 22 April 2016
      Source:Veterinary Microbiology
      Author(s): Julie Clasen, Anders Mellerup, John Elmerdahl Olsen, Øystein Angen, Anders Folkesson, Tariq Halasa, Nils Toft, Anna Camilla Birkegård
      The primary objective of this study was to determine the minimum number of individual fecal samples to pool together in order to obtain a representative sample for herd level quantification of antimicrobial resistance (AMR) genes in a Danish pig herd, using a novel high-throughput qPCR assay. The secondary objective was to assess the agreement between different methods of sample pooling. Quantification of AMR was achieved using a high-throughput qPCR method to quantify the levels of seven AMR genes (ermB, ermF, sulI, sulII, tet(M), tet(O) and tet(W)). A large variation in the levels of AMR genes was found between individual samples. As the number of samples in a pool increased, a decrease in sample variation was observed. It was concluded that the optimal pooling size is five samples, as an almost steady state in the variation was observed when pooling this number of samples. Good agreement between different pooling methods was found and the least time-consuming method of pooling, by transferring feces from each individual sample to a tube using a 10μl inoculation loop and adding 3.5ml of PBS, approximating a 10% solution, can therefore be used in future studies.

      PubDate: 2016-04-23T13:54:59Z
  • Thymic depletion of lymphocytes is associated with the virulence of
           PRRSV-1 strains
    • Abstract: Publication date: 30 May 2016
      Source:Veterinary Microbiology, Volume 188
      Author(s): Shyrley Paola Amarilla, Jaime Gómez-Laguna, Librado Carrasco, Irene M. Rodríguez-Gómez, José M. Caridad y Ocerín, Simon P. Graham, Jean-Pierre Frossard, Falko Steinbach, Francisco J. Salguero
      Porcine reproductive and respiratory syndrome virus (PRRSV) exists as two distinct viruses, type 1 (PRRSV-1) and type 2 (PRRSV-2). Atrophy of the thymus in PRRSV-2 infected piglets has been associated with a loss of thymocytes. The present study aimed to evaluate the impact of PRRSV-1 strains of differing virulence on the thymus of infected piglets by analysing the histomorphometry, the presence of apoptotic cells and cells producing cytokines. Thymic samples were taken from animals experimentally infected (with LV, SU1-bel, and 215-06 strains) or mock inoculated animals at 3, 7 and 35days post-infection (dpi) and processed for histopathological and immunohistochemical analyses. PRRSV antigen was detected in the thymus from 3dpi until the end of the study in all virus-infected animals with the highest numbers of infected cells detected in SU1-bel group. The histomorphometry analysis and counts of CD3+ thymocytes in the thymic cortex displayed significant differences between strains at different time-points (p ≤0.011), with SU1-bel group showing the most severe changes at 7dpi. Cell death displayed statistically significant increase in the cortex of all infected animals, with SU1-bel group showing the highest rate at 3 and 7dpi. The number of cells immunostained against IL-1α, TNF-α and IL-10 were predominantly detected in the medulla (p ≤0.01). An increase in the number of TNF-α and IL-10 positive cells was observed in LV and SU-1bel groups. Our results demonstrate that different PRRSV-1 strains induced depletion of the thymic cortex due to apoptosis of thymocytes and that the most severe depletion was associated with the highly virulent SU1-bel strain.

      PubDate: 2016-04-19T17:46:02Z
  • Chloroquine inhibits Rhodococcus equi replication in murine and foal
           alveolar macrophages by iron-starvation
    • Abstract: Publication date: 30 May 2016
      Source:Veterinary Microbiology, Volume 188
      Author(s): Leticia T. Gressler, Angela I. Bordin, Cole M. McQueen, Noah D. Cohen, Agueda Castagna de Vargas
      Rhodococcus equi preferentially infects macrophages causing pyogranulomatous pneumonia in young foals. Both the vapA and rhbC genes are up-regulated in an iron (Fe)-deprived environment, such as that found within macrophages. Chloroquine (CQ) is a drug widely used against malaria that suppresses the intracellular availability of Fe in eukaryotic cells. The main objective of this study was to evaluate the ability of CQ to inhibit replication of virulent R. equi within murine (J774A.1) and foal alveolar macrophages (AMs) and to verify whether the mechanism of inhibition could be Fe-deprivation-dependent. CQ effect on R. equi extracellular survival and toxicity to J774A.1 were evaluated. R. equi survival within J774A.1 and foal AMs was evaluated under CQ (10 and 20μM), bovine saturated transferrin (bHTF), and bovine unsaturated transferrin (bATF) exposure. To explore the action mechanism of CQ, the superoxide anion production, the lysozyme activity, as well as the relative mRNA expression of vapA and rhbC were examined. CQ at≤20μM had no effect on R. equi extracellular multiplication and J774A.1 viability. Exposure to CQ significantly and markedly reduced survival of R. equi within J774A.1 and foal AMs. Treatment with bHTF did not reverse CQ effect on R. equi. Exposure to CQ did not affected superoxide anion production or lysozyme activity, however vapA and rhbC expression was significantly increased. Our results reinforce the hypothesis that intracellular availability of Fe is required for R. equi survival, and our initial hypothesis that CQ can limit replication of R. equi in J774A.1 and foal AMs, most likely by Fe starvation.

      PubDate: 2016-04-15T17:12:37Z
  • Experimental induced avian E. coli salpingitis: Significant impact of
           strain and host factors on the clinical and pathological outcome
    • Abstract: Publication date: Available online 11 April 2016
      Source:Veterinary Microbiology
      Author(s): Rikke Heidemann Olsen, Ida Cecilie Naundrup Thøfner, Susanne Elisabeth Pors, Jens Peter Christensen
      Several types of Escherichia coli have been associated with extra-intestinal infections in poultry, however, they may vary significantly in their virulence potential. The aim of the present study was to investigate the virulence of five strains of E. coli obtained from different disease manifestations or from the cloacae of a healthy chicken. The virulence potential of the strains were evaluated in an avian experimental model for ascending infections, and experiments were conducted in both layers and broiler breeders. The clinical outcome of infection was highly depending on the challenge strain, however, not significantly reflecting the origin of the strain. In general, broiler breeders had a more severe clinical outcomes of infection compared to layers, but major with-in group diversity was observed for all challenge strains of clinical origin. A single strain of ST95 (phylogroup B2) had a distinct ability to cause disease. Results of the study shows major differences in virulence of different strains of E. coli in ascending infections; however, there was no indication of tissue-specific adaptation, since strains obtained from lesions unrelated to the reproductive system were fully capable of causing experimental infection. In conclusion, the study provides evidence for the clinical outcome of infection with E. coli in poultry is largely influenced by the specific strain as well as individual host factors.

      PubDate: 2016-04-12T13:07:28Z
  • Whole genome characterization of a G6P[5] rotavirus A strain isolated from
           a stray cat in Japan
    • Abstract: Publication date: Available online 8 April 2016
      Source:Veterinary Microbiology
      Author(s): Miho Kaneko, Masami Mochizuki, Osamu Nakagomi, Toyoko Nakagomi
      The whole genome of an unusual G6P[5] rotavirus A strain named FRV537, which was isolated from a stray cat in Japan, was characterized to determine its species of origin. The genotype constellation of FRV537 was G6-P[5]-I2-R2-C2-M2-A13-N2- T6-E2-H3. No known feline rotavirus has this genotype constellation; the Japanese equine strain OH-4 is the only known strain that does. While FRV537 shares the same genotype with some feline rotaviruses in all genes except those encoding VP4 and NSP1, none of these genes are closely related to those of known feline rotaviruses. By contrast, G6P[5] is almost exclusively present in bovine rotaviruses. The VP7 and VP4 genes of FRV537 formed a lineage with typical bovine rotaviruses with high bootstrap values. As to the internal capsid and nonstructural gene constellation, three bovine rotavirus strains had a constellation identical to that of FRV537. Moreover, each of the genotypes of FRV537 was found to be a common bovine genotype. In addition to the high nucleotide sequence identities between FRV537 and bovine rotaviruses in each genome segment (≥95%), phylogenetic analysis revealed a close relationship to bovine/artiodactyl rotaviruses. Thus, the molecular and phylogenetic evidence suggests that FRV537 isolated from a stray cat was of bovine rotavirus origin.

      PubDate: 2016-04-12T13:07:28Z
  • IFC - Aims & Scope, EDB, Publication Information
    • Abstract: Publication date: 1 May 2016
      Source:Veterinary Microbiology, Volume 187

      PubDate: 2016-04-12T13:07:28Z
  • Polarisation of equine pregnancy outcome associated with a maternal MHC
           class I allele: preliminary evidence
    • Abstract: Publication date: Available online 6 April 2016
      Source:Veterinary Microbiology
      Author(s): J.H. Kydd, R. Case, C. Winton, S. MacRae, E. Sharp, S.L. Ricketts, N. Rash, J.R. Newton
      Identification of risk factors which are associated with severe clinical signs can assist in the management of disease outbreaks and indicate future research areas. Pregnancy loss during late gestation in the mare compromises welfare, reduces fecundity and has financial implications for horse owners. This retrospective study focussed on the identification of risk factors associated with pregnancy loss among 46 Thoroughbred mares on a single British stud farm, with some but not all losses involving equid herpesvirus-1 (EHV-1) infection. In a sub-group of 30 mares, association between pregnancy loss and the presence of five common Thoroughbred horse haplotypes of the equine Major Histocompatibility Complex (MHC) was assessed. This involved development of sequence specific, reverse transcriptase polymerase chain reactions and in several mares, measurement of cytotoxic T lymphocyte activity. Of the 46 mares, 10 suffered late gestation pregnancy loss or neonatal foal death, five of which were EHV-1 positive. Maternal factors including age, parity, number of EHV-1 specific vaccinations and the number of days between final vaccination and foaling or abortion were not significantly associated with pregnancy loss. In contrast, a statistically significant association between the presence of the MHC class I B2 allele and pregnancy loss was identified, regardless of the fetus/foal’s EHV-1 status (p=0.002). In conclusion, this study demonstrated a significantly positive association between pregnancy loss in Thoroughbred mares and a specific MHC class I allele in the mother. This association requires independent validation and further investigation of the mechanism by which the mare’s genetic background contributes to pregnancy outcome.

      PubDate: 2016-04-07T21:01:16Z
  • Persistent spread of the rmtB 16S rRNA methyltransferase gene among
           Escherichia coli isolates from diseased food-producing animals in China
    • Abstract: Publication date: Available online 6 April 2016
      Source:Veterinary Microbiology
      Author(s): Jing Xia, Jian Sun, Ke Cheng, Liang Li, Liang-Xing Fang, Meng-Ting Zou, Xiao-Ping Liao, Ya-Hong Liu
      A total of 963 non-duplicate E. coli strains isolated from food-producing animals between 2002 and 2012 were screened for the presence of the 16S rRNA methyltransferase genes. Among the positive isolates, resistance determinants to extended spectrum β-lactamases, plasmid-mediated quinolone resistance genes as well as floR and fosA/A3/C2 were detected using PCR analysis. These isolates were further subjected to antimicrobial susceptibility testing, molecular typing, PCR-based plasmid replicon typing and plasmid analysis. Of the 963 E. coli isolates, 173 (18.0%), 3 (0.3%) and 2 (0.2%) were rmtB-, armA- and rmtE- positive strains, respectively. All the 16S rRNA methyltransferase gene-positive isolates were multidrug resistant and over 90% of them carried one or more type of resistance gene. IncF (especially IncFII) and non-typeable plasmids played the main role in the dissemination of rmtB, followed by the IncN plasmids. Plasmids that harbored rmtB ranged in size from 20kb to 340kb. EcoRI-RFLP testing of the 109 rmtB-positive plasmids from different years and different origins suggested that horizontal (among diverse animals) and vertical transfer of IncF, non-typeable and IncN-type plasmids were responsible for the spread of rmtB gene. In summary, our findings highlight that rmtB was the most prevalent 16S rRNA methyltransferase gene, which present persistent spread in food-producing animals in China and a diverse group of plasmids was responsible for rmtB dissemination.

      PubDate: 2016-04-07T21:01:16Z
  • Microbiome associations in pigs with the best and worst clinical outcomes
           following co-infection with porcine reproductive and respiratory syndrome
           virus (PRRSV) and porcine circovirus type 2 (PCV2)
    • Abstract: Publication date: 30 May 2016
      Source:Veterinary Microbiology, Volume 188
      Author(s): Megan C. Niederwerder, Crystal J. Jaing, James B. Thissen, Ada Giselle Cino-Ozuna, Kevin S. McLoughlin, Raymond R.R. Rowland
      On a world-wide basis, co-infections involving porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are common and contribute to a range of polymicrobial disease syndromes in swine. Both viruses compromise host defenses, resulting in increased susceptibility to infections by primary and secondary pathogens that can affect growth performance as well as increased morbidity and mortality. An experimental population of 95 pigs was co-infected with PRRSV and PCV2. At 70days post-infection (dpi), 20 representative pigs were selected as having the best or worst clinical outcome based on average daily gain (ADG) and the presence of clinical disease. Worst clinical outcome pigs had prolonged and greater levels of viremia as measured by qPCR. Serum, lung and fecal samples collected at 70 dpi were analyzed using a comprehensive DNA microarray technology, the Lawrence Livermore Microbial Detection Array, to detect over 8000 microbes. Bacterial species, such as Bacillus cereus, were detected at a higher rate in the serum of worst performing pigs. At the level of the fecal microbiome, the overall microbial diversity was lower in the worst clinical outcome group. The results reinforce the importance of pathogen load in determining clinical outcome and suggest an important role of microbial diversity as a contributing factor in disease.

      PubDate: 2016-04-07T21:01:16Z
  • Lethal dose and clinical signs of Aeromonas hydrophila in Arapaima gigas
           (Arapaimidae), the giant fish from Amazon
    • Abstract: Publication date: Available online 2 April 2016
      Source:Veterinary Microbiology
      Author(s): Marcia K.R. Dias, Luciana S. Sampaio, Aldo A. Proietti-Junior, Eliane T.O. Yoshioka, Dália P. Rodrigues, Anselmo F.R. Rodriguez, Ricardo A. Ribeiro, Fernando E.S.E.D.V. Faria, Rodrigo O.A. Ozório, Marcos Tavares-Dias
      Aeromonas hydrophila is causing substantial economic losses in world aquaculture. This study determined the tolerance limit (LD50-96h) of A. hydrophila in Arapaima gigas, and also investigated the clinical signs after intradermal inoculation. Arapaima gigas fingerlings were inoculated intraperitoneally with 0 (control), 1.0×105, 1.0×106, 1.0×107, 1.0×109 and 1.0×1010 CFU/mL of A. hydrophila for the determination of LD50-96h, which was 1.8×108 CFU/mL. In another trial with intradermal inoculation of 1.8×108 CFU/mL A. hydrophila, there was a 91.6% of mortality between 8–23h, and several clinical signs were found. As follows: depigmentation in the tegument, lesions in the tail and fins, loss of balance, reduction of respiratory movements, hemorrhagic foci, necrotic hemorrhages in the kidney, liver and swim bladder, splenomegaly, ascites in the abdominal cavity and hyperemia, enlargement of the gall bladder, among other clinical signs observed. The results showed that A. gigas has a relative tolerance to A. hydrophila when compared to other Neotropical fish species.

      PubDate: 2016-04-03T20:32:54Z
  • Evolution of the nasopharyngeal microbiota of beef cattle from weaning to
           40days after arrival at a feedlot
    • Abstract: Publication date: Available online 26 March 2016
      Source:Veterinary Microbiology
      Author(s): Edouard Timsit, Matthew Workentine, Anthony B. Schryvers, Devin B. Holman, Frank van der Meer, Trevor W. Alexander
      Bovine respiratory disease complex (BRDc) is a major cause of morbidity and mortality in beef cattle. There is recent evidence suggesting that the nasopharyngeal microbiota has a key role in respiratory health and disease susceptibility in cattle. However, there is a paucity of knowledge regarding evolution of the nasopharyngeal microbiota when cattle are most likely to develop BRDc (i.e. from weaning to 40days after arrival at a feedlot). The objective was to describe the evolution of the nasopharyngeal microbiota of beef cattle from weaning to 40days after arrival at a feedlot. Deep nasal swabs (DNS) from 30 Angus-cross steers were collected at weaning, on arrival at a feedlot, and at day 40 after arrival. The DNA was extracted from DNS and the hypervariable region V3 of the 16S rRNA gene was amplified and sequenced (Illumina MiSeq platform). Nasopharyngeal microbiota underwent a profound evolution from weaning to arrival at the feedlot and from arrival to day 40, with the abundance of 92 Operational Taxonomic Units (OTUs) significantly changing over time. Mycoplasma (M. dispar and M. bovirhinis) was the most abundant genus in the nasopharynx, accounting for 53% of the total bacterial population. Because an evolving bacterial community may be less capable of resisting colonization by pathogenic bacteria, the instability of the nasopharyngeal microbiota documented in this study might explain why cattle are most likely to be affected with BRDc during the first weeks after weaning and arrival at a feedlot.

      PubDate: 2016-03-26T19:53:26Z
  • A Streptococcus suis LysM domain surface protein contributes to bacterial
    • Abstract: Publication date: Available online 25 March 2016
      Source:Veterinary Microbiology
      Author(s): Zongfu Wu, Jing Shao, Haiyan Ren, Huanyu Tang, Mingyao Zhou, Jiao Dai, Liying Lai, Huochun Yao, Hongjie Fan, Dai Chen, Jie Zong, Chengping Lu
      Streptococcus suis (SS) is a major swine pathogen, as well as a zoonotic agent for humans. Numerous factors contribute to SS virulence, but the pathogenesis of SS infection is poorly understood. Here, we show that a novel SS surface protein containing a LysM at the N-terminus (SS9-LysM) contributes to SS virulence. Homology analysis revealed that the amino acid sequence of SS9-LysM from the SS strain, GZ0565, shares 99.8–68.7% identity with homologous proteins from other SS strains and 41.2% identity with Group B Streptococcal protective antigen Sip. Immunization experiments showed that 7 out of 30 mice immunized with recombinant SS9-LysM were protected against challenge with the virulent GZ0565 strain, while all of the control mice died within 48h following bacterial challenge. In mouse infection model, the virulence of the SS9-LysM deletion mutant (ΔSS9-LysM) was reduced compared with the wild-type (WT) strain GZ0565 and SS9-LysM complemented strain. In addition, ΔSS9-LysM was significantly more sensitive to killing by pig blood ex vivo and mouse blood in vivo compared with the WT strain and SS9-LysM complemented strain. In vivo transcriptome analysis in mouse blood showed that the WT strain reduced the expression of host genes related to iron-binding by SS9-LysM. Moreover, the total free iron concentration in blood from infected mice was significantly lower for the ΔSS9-LysM strain compared with the WT strain. Together, our data reveal that SS9-LysM facilitates SS survival within blood by releasing more free iron from the host. This represents a new mechanism of SS pathogenesis.

      PubDate: 2016-03-26T19:53:26Z
  • IFC - Aims & Scope, EDB, Publication Information
    • Abstract: Publication date: 15 April 2016
      Source:Veterinary Microbiology, Volume 186

      PubDate: 2016-03-26T19:53:26Z
    • Abstract: Publication date: Available online 19 March 2016
      Source:Veterinary Microbiology
      Author(s): Kevin Yana Njabo, Linda Zanontian, Basma N. Sheta, Ahmed Samy, Shereen Galal, Frederic Paik Schoenberg, Thomas B Smith
      H5N1 highly pathogenic avian influenza virus (HPAIV) continues to cause mortality in poultry and threaten human health at a panzootic scale in Egypt since it was reported in 2006. While the early focus has been in Asia, recent evidence suggests that Egypt is an emerging epicenter for the disease. Despite control measures, epizootic transmission of the disease continues. Here, we investigate the persistence of HPAIV across wild passerine birds and domestic poultry between 2009 and 2012 and the potential risk for continuous viral transmission in Egypt. We use a new weighted cross J-function to investigate the degree and spatial temporal nature of the clustering between sightings of infected birds of different types, and the risk of infection associated with direct contact with infected birds. While we found no infection in wild birds, outbreaks occurred year round between 2009–2012, with a positive interaction between chickens and ducks. The disease was more present in the years 2010 and 2011 coinciding with the political unrest in the country. Egypt thus continues to experience endemic outbreaks of avian influenza HPAIV in poultry and an increased potential risk of infection to other species including humans. With the current trends, the elimination of the HPAIV infection is highly unlikely without a complete revamp of current policies. The application of spatial statistics techniques to these types of data may help us to understand the characteristics of the disease and may subsequently allow practitioners to explore possible preventive solutions.

      PubDate: 2016-03-21T19:27:23Z
  • Highly pathogenic avian influenza viruses H5N2, H5N3, and H5N8 in Taiwan
           in 2015
    • Abstract: Publication date: Available online 19 March 2016
      Source:Veterinary Microbiology
      Author(s): Ming-Shiuh Lee, Li-Hsuan Chen, Yen-Ping Chen, Yu-Pin Liu, Wan-Chen Li, Yeou-Liang Lin, Fan Lee
      A severe epidemic, affecting mainly goose populations, broke out in early January 2015.The causative agents were identified as novel H5 avian influenza viruses carrying N2, N3, and N8 subtypes of the neuraminidase gene. From January 8 to February 11, 766 waterfowl and poultry farms were invaded by the H5 viruses, and more than 2.2 million geese died or were culled. Phylogenetic analysis suggested that these avian influenza viruses derived from the H5 viruses of clade which were emerging in 2014 in East Asia, West Europe, and North America.

      PubDate: 2016-03-21T19:27:23Z
  • In vivo virulence of viral haemorrhagic septicaemia virus (VHSV) in
           rainbow trout Oncorhynchus mykiss correlates inversely with in vitro Mx
           gene expression
    • Abstract: Publication date: 1 May 2016
      Source:Veterinary Microbiology, Volume 187
      Author(s): Irene Cano, Bertrand Collet, Clarissa Pereira, Richard Paley, Ronny van Aerle, David Stone, Nick G.H. Taylor
      The in vitro replication of viral haemorrhagic septicaemia virus (VHSV) isolates from each VHSV genotype and the associated cellular host Mx gene expression were analysed. All the isolates were able to infect RTG-2 cells and induce increased Mx gene expression (generic assay detecting isoforms 1 and 3 [Mx1/3]). A trout pathogenic, genotype Ia isolate (J167), showing high replication in RTG-2 cells (by infective titre and N gene expression) induced lower Mx1/3 gene expression than observed in VHSV isolates known to be non-pathogenic to rainbow trout: 96-43/8, 96-43/10 (Ib); 1p49, 1p53 (II); and MI03 (IVb). Paired co-inoculation assays were analysed using equal number of plaque forming units per ml (PFU) of J167 (Ia genotype) with other less pathogenic VHSV genotypes. In these co-inoculations, the Mx1/3 gene expression was significantly lower than for the non-pathogenic isolate alone. Of the three rainbow trout Mx isoforms, J167 did not induce Mx1 up-regulation in RTG-2 or RTgill-W1 cells. Co-inoculating isolates resulted in greater inhibition of Mx in both rainbow trout cell lines studied. Up-regulation of sea bream Mx in SAF-1 cells induced by 96-43/8 was also lower in co-inoculation assays with J167. The RTG-P1 cell line, expressing luciferase under the control of the interferon-induced Mx rainbow trout gene promoter, showed low luciferase activity when inoculated with pathogenic strains: J167, DK-5131 (Ic), NO-A-163/68 (Id), TR-206239-1, TR-22207111 (Ie), 99-292 (IVa), and CA-NB00-01 (IVc). Co-inoculation assays showed a J167-dose dependent inhibition of the luciferase activity. The data suggest that virulent VHSV isolates may interfere in the interferon pathways, potentially determining higher pathogenicity.

      PubDate: 2016-03-21T19:27:23Z
  • Identification of amino acids in H9N2 influenza virus neuraminidase that
           are critical for the binding of two mouse monoclonal antibodies
    • Abstract: Publication date: Available online 16 March 2016
      Source:Veterinary Microbiology
      Author(s): Zhimin Wan, Jianqiang Ye, Jianjun Sang, Hongxia Shao, KunQian, Wenjie Jin, Aijian Qin, Hongquan Wan
      Neuraminidase (NA) is one of the major glycoproteins on the surface of influenza virus. It cleaves the linkage between haemagglutinin and cell surface receptors, and thus helps the release and spread of influenza virus. Despite the importance of H9N2 virus in influenza pandemic preparedness, the antigenic characteristics of its surface glycoproteins, especially NA, remains to be investigated. In the present study, we characterized two monoclonal antibodies (mAbs), 1D1 and 1G8, which are against the NA of an H9N2 virus A/Chicken/Jiangsu/X1/2004 (X1). We examined the inhibitory effect of these mAbs in two NA inhibition assays: enzyme-linked lectin assay (ELLA) and 2′-(4-methylumbelliferyl)-a-D-N-acetylneuraminic acid (Mu-NANA) assay. In ELLA, which uses a large molecule fetuin (molecular weight: 50 kd) as substrate, both antibodies effectively inhibit the NA activity of X1 virus. However, in Mu-NANA assay, which uses the small molecule Mu-NANA (molecular weight: 489 d) as substrate, antibody 1G8 inhibits the NA activity, while antibody 1D1 does not. Three amino acid mutations, at positions 198, 199 and 338, respectively, were detected in the NA of escape mutants of X1 virus selected with the two antibodies. Natural mutations at these three positions have occurred, indicative of immune pressure on H9N2 virus in the field. Our findings lay a basis for detailed investigation on the antigenic structure of H9N2 virus NA, which may be helpful for developing NA-based antibody reagents as well as vaccines.

      PubDate: 2016-03-17T19:06:58Z
  • Low prevalence of porcine circovirus type 2 infections in farrowing sows
           and corresponding pre-suckling piglets in southern German pig farms
    • Abstract: Publication date: Available online 16 March 2016
      Source:Veterinary Microbiology
      Author(s): M. Eddicks, M. Mueller, S. Willi, R. Fux, S. Reese, G. Sutter, J. Stadler, M. Ritzmann
      Porcine circovirus type 2 (PCV2) is the assumed causative agent of a number of different diseases summarized as porcine circovirus diseases (PCVD). The virus is shed via different se- and excretions of PCV2 infected pigs. Transmission of the virus occurs horizontally and vertically either by oronasal or diaplacental infection. Recent research emphasizes the importance of diaplacental PCV2 infection or the infection in early stages of the piglet’s life attributable to excretion of PCV2 by the dams within the suckling period. To estimate the prevalence of intrauterine PCV2 infections under field conditions in Bavaria the PCV2 status of farrowing sows (n=198) and corresponding pre-suckling piglets (n=590) of 20 piglet producing farms was examined. PCV2 viral load and anti-PCV2 antibodies in the serum of the sows and piglets were examined at time of farrowing or before colostrum intake, respectively. PCV2 excretion of the sows via saliva, feces and urine was examined additionally. PCV2 specific antibodies in the serum of the sows were detectable on 11 farms with a mean in herd seroprevalence of 35.5% in these farms. Only 0.65% of all samples collected from 198 sows were positive for PCV2 DNA (serum: 1%; feces: 0.5%; saliva: 0.5%; urine: 0.6%). PCV2 DNA was detectable in sample material from seronegative sows as well as from seropositive sows. In none of the pre-suckling serum samples of the piglets IgG antibodies against PCV2 or PCV2 DNA were present. No correlation between the antibody- and viremia status of the sows and the PCV2 excretion was detectable. In contrast to reports about a high prevalence of viremic pre-suckling piglets in the suckling period in North America, the results of the present study reveal that diaplacental infection with PCV2 is comparatively rare in Southern Germany and infection of piglets within the suckling period seems to be more likely.

      PubDate: 2016-03-17T19:06:58Z
  • Controlling equine influenza: traditional to next generation serological
    • Abstract: Publication date: Available online 10 March 2016
      Source:Veterinary Microbiology
      Author(s): Rebecca Kinsley, Simon D. Scott, Janet M. Daly
      Serological assays provide an indirect route for the recognition of infectious agents via the detection of antibodies against the infectious agent of interest within serum. Serological assays for equine influenza A virus can be applied for different purposes: diagnosing infections; subtyping isolates; surveillance of circulating strains; and to evaluate the efficacy of vaccines before they reach the market. Haemagglutination inhibition (HI) and single radial haemolysis (SRH) assays are most commonly used in the equine field. This review outlines how both these assays together with virus neutralization (VN) and ELISA are performed, interpreted and applied for the control of equine influenza, giving the limitations and advantages of each. The pseudotyped virus neutralization assay (PVNA) is also discussed as a promising prospect for the future of equine influenza virus serology.

      PubDate: 2016-03-13T18:46:19Z
  • Serologically silent, occult equine infectious anemia virus (EIAV)
           infections in horses.
    • Abstract: Publication date: Available online 11 March 2016
      Source:Veterinary Microbiology
      Author(s): Sonia Ricotti, Maria Inés Garcia, Carolina Veaute, Alejandra Bailat, Eduardo Lucca, R. Frank Cook, Sheila J. Cook, Adriana Soutullo
      Molecular and serological techniques for Equine Infectious Anemia Virus (EIAV) diagnosis were compared using samples from 59 clinically normal horses stabled on five farms in the Santa Fe Province of Argentina. Of these 26 (44.1%) were positive in official AGID tests and/or gp45/gp90-based ELISA. Surprisingly 18 of the 33 seronegative horses were positive in a PCR against viral sequences encoding gp45 (PCR-positive/AGID-negative) with all but one remaining EIAV-antibody negative throughout a two year observation period. The gp45 PCR results are supported by fact that 7/18 of these horses were positive in the Office International des Epizooties (OIE) recommended EIAV gag gene specific PCR plus 2 of this 7 also reacted in a PCR directed predominantly against the 5′ untranslated region of the viral genome. Furthermore sufficient quantities of serum were available from 8 of these horses to verify their seronegative status in sensitive Western Blot tests and demonstrate by ELISA the absence of EIAV-specific antibodies was not attributable to abnormalities in total IgG concentration. Studies involving 7 of the PCR-positive/AGID-negative horses to measure lymphocyte proliferation in the presence of PHA showed no significant differences between this group and control animals. In addition, lymphocytes from 2 of these 7 horses responded to peptides derived from gp90 and gp45. Together these results demonstrate that apparently clinically normal horses with no gross signs of immunodeficiency in terms of total IgG concentration or T helper-cell function can remain seronegative for at least 24 months while harboring EIAV specific nucleic acid sequences.

      PubDate: 2016-03-13T18:46:19Z
  • Susceptibility of goldsinny wrasse, Ctenolabrus rupestris L. (Labridae),
           to viral haemorrhagic septicaemia virus (VHSV) genotype III: Experimental
           challenge and pathology
    • Abstract: Publication date: 15 April 2016
      Source:Veterinary Microbiology, Volume 186
      Author(s): I. Matejusova, P.A. Noguera, M. Hall, A.J.A. McBeath, K. Urquhart, J. Simons, M.J. Fordyce, K. Lester, Y.-M. Ho, W. Murray, D.W. Bruno
      Cleaner fish, such as wrasse, are being increasingly used to combat the sea lice infestation of Atlantic salmon (Salmo salar L.) in many European countries. To determine susceptibility of the goldsinny wrasse (Ctenolabrus rupestris L.) and pathogenesis of the viral haemorrhagic septicaemia virus (VHSV) genotype III isolate 12-654, previously associated with VHSV infection in the Shetland Islands in 2012, fish were experimentally challenged by intraperitoneal injection (IP), bath immersion and cohabitation routes. Cumulative proportion of moribund wrasse reached 17% following the virus immersion challenge while by the IP-route moribunds exceeded 50% within 14days post-challenge. Typical signs of VHS as reported in rainbow trout (Oncorhynchus mykiss), were not observed in moribund goldsinny wrasse. The most pronounced histopathological changes, consistent regardless of the route of infection, were observed within the heart and included atrium myofibril degeneration, focal infiltration and multifocal necrosis, with prominent swelling of the endocardium and occasional detachment. Pathological changes in the atrium were associated with presence of the viral antigen as confirmed by a positive immunohistochemical staining. Virus clearance and heart tissue recovery were noted although further experiments are required to confirm these observations. The results of a cohabitation experiment confirmed that goldsinny wrasse shed viable virus and therefore represent a risk of virus transmission to other VHSV susceptible species. Similarities between the pathology in goldsinny wrasse induced through the controlled experimental challenges and that of wrasse spp. from an infection occurrence in Shetland are discussed.

      PubDate: 2016-03-13T18:46:19Z
  • Pathogenicity and genetic characteristics associated with cell adaptation
           of a virulent porcine reproductive and respiratory syndrome virus nsp2 DEL
           strain CA-2
    • Abstract: Publication date: Available online 5 March 2016
      Source:Veterinary Microbiology
      Author(s): Seung-Chul Lee, Hwan-Won Choi, Eeuri Nam, Yun-Hee Noh, Sunhee Lee, Yoo Jin Lee, Gun-Seok Park, Jae-Ho Shin, In-Joong Yoon, Shien-Young Kang, Changhee Lee
      Porcine reproductive and respiratory syndrome virus (PRRSV) is the most common and world-widespread viral pathogen of swine. We previously reported genomic sequences and pathogenicity of type 2 Korean PRRSV strains belonging to the virulent lineage 1 family, which contain remarkable amino acid deletions in nonstructural protein 2 (nsp2 DEL) compared to VR-2332. Here, a virulent type 2 Korean PRRSV nsp2 DEL strain, CA-2, was serially propagated in MARC-145 cells for up to 100 passages (CA-2-P100). As the passage number increased, the phenotypic characteristics of cell-adapted CA-2 strains were altered, in terms of higher viral titers and larger plaque sizes compared to the parental virus. Pro-inflammatory cytokine genes, including TNF-α, IL-8, MCP-1, and MCP-2, were found to be significantly down-regulated in PAM cells with the CA-2-P100 strain compared to its parental nsp2 DEL virus. Animal inoculation studies demonstrated that the virulence of CA-2-P100 was reduced significantly, with showing normal weight gain, body temperatures, and lung lesions comparable to the control group. Furthermore, high-passage CA-2-P100 showed declined and transient viremia kinetics, as well as delayed and low PRRSV-specific antibody responses in infected pigs. In addition, we determined whole genome sequences of low to high-passage derivatives of CA-2. The nsp2 DEL pattern was conserved for 100 passages, whereas no other deletions or insertions arose during the cell adaptation process. However, CA-2-P100 possessed 54 random nucleotide substitutions that resulted in 27 amino acid changes distributed throughout the genome, suggesting that these genetic drifts provide a possible molecular basis correlated with the cell-adapted features in vitro and the attenuated phenotype in vivo. Taken together, our data indicate that the cell-attenuated CA-2-P100 strain is a promising candidate for developing a safe and effective live PRRSV vaccine.

      PubDate: 2016-03-09T18:32:21Z
  • Downregulation of Protein Kinase PKR Activation by Porcine Reproductive
           and Respiratory Syndrome Virus at Its Early Stage Infection
    • Abstract: Publication date: Available online 7 March 2016
      Source:Veterinary Microbiology
      Author(s): Yueqiang Xiao, Zexu Ma, Rong Wang, Liping Yang, Yuchen Nan, Yan-Jin Zhang
      The interferon-induced double-strand RNA activated protein kinase (PKR) plays an important role in antiviral response. The objective of this study was to assess the effect of porcine reproductive and respiratory syndrome virus (PRRSV) on PKR activation. Here we report that PRRSV inhibited PKR activation during its early stage infection of primary pulmonary alveolar macrophages (PAMs). PRRSV infection led to lower level of phosphorylated PKR in comparison with mock-infected cells. The PKR inhibition was sustained until 10hours post infection in the presence of polyI:C, a synthetic analog of double-stranded RNA activating PKR. PKR-mediated phosphorylation of the eukaryotic translation initiation factor eIF2α was also lower in the PRRSV-infected PAMs during the early stage infection. Interestingly, inactivated PRRSV was capable to inhibit the PKR activation until 6hours post infection. This suggests that structural components of PRRSV virions were responsible for the inhibition, although PRRSV replication was needed for longer inhibition. These results indicate that the downregulation of PKR activation during early infection stage should be essential for PRRSV to avoid the antiviral response to initiate replication. This finding contributes to our understanding on PRRSV interaction with host innate immune response and reveal a target for control of PRRSV infection.

      PubDate: 2016-03-09T18:32:21Z
  • Prophylactic potential of resiquimod against very virulent infectious
           bursal disease virus (vvIBDV) challenge in chicken
    • Abstract: Publication date: Available online 9 March 2016
      Source:Veterinary Microbiology
      Author(s): Arunsaravanakumar Annamalai, Saravanan Ramakrishnan, Swati Sachan, B.S. Anand Kumar, Bal Krishan Sharma, Vimal Kumar, Munuswamy Palanivelu, Berin P. Varghese, Ajay Kumar, B.C. Saravanan, Narayanan Krishnaswamy
      The study evaluated the prophylactic potential of resiquimod (R-848), a synthetic TLR7 agonist, against very virulent infectious bursal disease virus (vvIBDV) infection in chicken. Specific pathogen free White Leghorn chicks of three week age were treated with R-848 (50μg/bird, intramuscular) or PBS (n=26/group). Twenty four hour later, half of the birds from each group were challenged with 105 ELD50 of vvIBDV and observed for 10 days. To understand the effect of R-848, immune response genes such as interferon (IFN)-β, IFN-γ, IL-1β, IL-4, iNOS and TLR7 were analyzed at 24 and 48h post-challenge in PBMCs ex vivo by real-time PCR (n=6/group). On day 4 post-challenge, representative birds (n=3/group) were sacrificed to study the bursal damage and IBDV antigen clearance. Immunosuppression was assessed by antibody response against live Newcastle disease virus (NDV) vaccine, which was administered on day 10 post-challenge. R-848 pre-treatment significantly up-regulated the transcripts of each immune response gene studied (P < 0.05). There was 50% mortality on vvIBDV challenge in control birds, while it was only 20% with R-848 group. R-848 pre-treatment reduced the bursal damage as indicated by lower bursal lesion score in histopathology, reduced IBDV antigen signal in immunohistochemistry and improved antigen clearance in agar gel immunodiffusion test. Further, it protected significantly against vvIBDV induced immunosuppression as indicated by HI antibody titre. It is concluded that pre-treatment of R-848 conferred partial protection from mortality and bursal damage while complete protection against immunosuppression in chicken when challenged with vvIBDV, which could be due to the up-regulation of immune response genes.

      PubDate: 2016-03-09T18:32:21Z
  • Potential bacterial core species associated with digital dermatitis in
           cattle herds identified by molecular profiling of interdigital skin
    • Abstract: Publication date: 15 April 2016
      Source:Veterinary Microbiology, Volume 186
      Author(s): Martin W. Nielsen, Mikael L. Strube, Anastasia Isbrand, Worood D.H.M. Al-Medrasi, Mette Boye, Tim K. Jensen, Kirstine Klitgaard
      Although treponemes are consistently identified in tissue from bovine digital dermatitis (DD) lesions, the definitive etiology of this debilitating polymicrobial disease is still unresolved. To study the microbiomes of 27 DD-infected and 10 healthy interdigital skin samples, we used a combination of different molecular methods. Deep sequencing of the 16S rRNA gene variable regions V1–V2 showed that Treponema, Mycoplasma, Fusobacterium and Porphyromonas were the genera best differentiating the DD samples from the controls. Additional deep sequencing analysis of the most abundant genus, Treponema, targeting another variable region of the 16S rRNA gene, V3–V4, identified 15 different phylotypes, among which Treponema phagedenis-like and Treponema refringens-like species were the most abundant. Although the presence of Treponema spp., Fusobacterium necrophorum and Porphyromonas levii was confirmed by fluorescence in situ hybridization (FISH), the results for Mycoplasma spp. were inconclusive. Extensive treponemal epidermal infiltration, constituting more than 90% of the total bacterial population, was observed in 24 of the 27 DD samples. F. necrophorum and P. levii were superficially located in the epidermal lesions and were present in only a subset of samples. RT-qPCR analysis showed that treponemes were also actively expressing a panel of virulence factors at the site of infection. Our results further support the hypothesis that species belonging to the genus Treponema are major pathogens of DD and also provide sufficient clues to motivate additional research into the role of M. fermentans, F. necrophorum and P. levii in the etiology of DD.

      PubDate: 2016-03-09T18:32:21Z
  • Spillback transmission of European H1N1 avian-like swine influenza viruses
           to turkeys: A strain-dependent possibility'
    • Abstract: Publication date: Available online 27 February 2016
      Source:Veterinary Microbiology
      Author(s): Francesco Bonfante, Alice Fusaro, Luca Tassoni, Livia Victoria Patrono, Milani Adelaide, Silvia Maniero, Annalisa Salviato, Calogero Terregino
      In 1979, an avian influenza virus of the H1N1 subtype began to circulate in European swine herds, rapidly replacing classical swine H1N1 viruses. Spill-back transmissions to turkeys were recorded occasionally, but they might have been underreported due to the asymptomatic nature of the infection and the lack of specific surveillance. In our study, we evaluated the infectivity and transmissibility in turkeys of seven strains of H1N1 avian-like swine viruses isolated from 1979 to 2006, and compared them with their closest progenitor A/duck/Bavaria/1/77 (H1N1), to establish whether the adaptation to pigs has gradually decreased their fitness in turkeys. Our data indicate that the circulation of European H1N1 in pigs might have impaired the possibility of infecting turkeys. Nevertheless, the two swine-origin strains, which showed the ability to replicate and transmit in turkeys, possess typical swine-like genetic traits, not different from the rest of the tested isolates, suggesting replication of avian-like swine H1N1 viruses in turkeys as a strain-dependent polygenic feature.

      PubDate: 2016-03-04T18:16:05Z
  • The functions of the variable lipoprotein family of Mycoplasma hyorhinis
           in adherence to host cells
    • Abstract: Publication date: 15 April 2016
      Source:Veterinary Microbiology, Volume 186
      Author(s): Qiyan Xiong, Jia Wang, Yan Ji, Bo Ni, Bixiong Zhang, Qinghong Ma, Yanna Wei, Shaobo Xiao, Zhixin Feng, Maojun Liu, Guoqing Shao
      Mycoplasma hyorhinis (M. hyorhinis) is a swine pathogen that is associated with various human cancers and contamination in cell cultures. However, no studies on the adhesion molecules of this pathogen have yet been reported. The variable lipoprotein (Vlp) family is an important surface component of M. hyorhinis. Herein, we performed several experiments to identify the function of the Vlp family in adherence to host cells. Seven recombinant Vlp (rVlp) proteins were expressed in Escherichia coli and purified by affinity chromatography. The potential role of rVlp adherence to pig kidney (PK-15) and swine tracheal epithelial (STEC) cells was then studied by indirect immunofluorescence assay and microtiter plate adherence assay. Adhesion of M. hyorhinis to PK-15 and STEC cells was specifically inhibited by the addition of a cocktail of rVlp proteins. The rVlp protein mixture was shown to bind to both PK-15 and STEC cells. The binding increased in a dose-dependent manner and could be blocked by antisera against the rVlp proteins. Most of the rVlp proteins could bind individually to both PK-15 and STEC cells except for rVlpD and rVlpF, which bound only to STEC cells. Because Vlp members vary in size among different strains and generations, they may vary in their cytoadhesion capabilities in various strains. In summary, the present results indicate that the Vlp family functions as adhesins of M. hyorhinis.

      PubDate: 2016-03-04T18:16:05Z
  • Adaptive amino acid substitutions enhance the virulence of a novel human
           H7N9 influenza virus in mice
    • Abstract: Publication date: Available online 3 March 2016
      Source:Veterinary Microbiology
      Author(s): Yongkun Zhao, Zhijun Yu, Linna Liu, Tiecheng Wang, Weiyang Sun, Chengyu Wang, Zhiping Xia, Yuwei Gao, Bo Zhou, Jun Qian, Xianzhu Xia
      To identify molecular features that confer enhanced H7N9 virulence in mammals, we independently generated three mouse-adapted variants of A/Shanghai/2/2013 (H7N9) by serial passage in mice. The mouse lethal doses (MLD50) of the mouse-adapted variants were reduced>1000 to 100000-fold when compared to the parental virus. Adapted variants displayed enhanced replication kinetics in vivo, and were capable of replicating in multiple organs. Analysis of adapted viral genomes revealed a total of 14 amino acid changes among the three variant viruses in the PA (T97I, K328R, P332T, and Q556R), HA (H3 numbering; A107T, R220I, L226Q, and R354K), NP (A284T and M352I), NA (M26I, N142S, and G389D), and M1 (M128R) proteins. Notably, many of these adaptive amino acid changes have been identified in naturally occurring H7 isolates. Our results identify amino acid substitutions that collectively enhance the ability of a human H7N9 virus to replicate and cause severe disease in mice.

      PubDate: 2016-03-04T18:16:05Z
  • Salmonella Typhimurium infection primes a nutriprive mechanism in piglets
    • Abstract: Publication date: Available online 4 March 2016
      Source:Veterinary Microbiology
      Author(s): Maria Miarelli, Rosanna Drumo, Federica Signorelli, Cinzia Marchitelli, Silvia Pavone, Michele Pesciaroli, Jessica Ruggieri, Barbara Chirullo, Serena Ammendola, Andrea Battistoni, Giovanni L Alborali, Elisabetta Manuali, Paolo Pasquali
      Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important cause of acute food- borne zoonoses worldwide, typically carried by pigs. It is well known that Salmonella has evolved a wide array of strategies enabling it to invade the host, but little information is available on the specific host responses to Salmonella infections. In the present study, we used an in vivo approach (involving piglets infected with a virulent or an attenuated S. Typhimurium strain) coupled to histological and proteomic analysis of the cecum mucosa, to highlight the host pathways activated during S. Typhimurium infection. We confirm the complex host-pathogen interaction. Our data showed that the metabolic and the cytoskeleton organization functions were the most significantly altered. In particular, the modifications of energy metabolic pathway could suggest a “nutriprive” mechanism, in which the host reduce its metabolic and energetic status to limit Salmonella infection. This study could represent a preliminary approach, providing information useful to better understand the host-Salmonella interaction.

      PubDate: 2016-03-04T18:16:05Z
  • Molecular analysis of hemagglutinin-1 fragment of avian influenza H5N1
           viruses isolated from chicken farms in Indonesia from 2008–2010
    • Abstract: Publication date: Available online 26 February 2016
      Source:Veterinary Microbiology
      Author(s): Gusti N. Mahardika, Melina Jonas, Theresia Murwijati, Nur Fitria, I. Nyoman Suartha, I. Gusti A.A. Suartini, I. Wayan Teguh Wibawan
      Highly pathogenic avian influenza virus of subtype H5N1 (AIV-H5N1) has been circulating in Indonesia since 2003. To understand the genetic diversity of these viruses, and to predict vaccine efficacy, the hemaglutinin-1 (HA-1) fragment of viruses isolated from chicken farms in Indonesia from 2008–2010 was sequenced and analyzed. The effects of these molecular changes were investigated in challenge experiments and HI assays of homologous and heterologous strains. Molecular analysis showed that these AIV-H5N1 isolates had evolved into three distinct sub-lineages from an ancestor circulating since 2003. Although no significant positive selection of residues was detected, 12 negatively selected sites were identified (p <0.05). Moreover, four sites showed evidence of significant episodic diversifying selection. The findings indicated complete protectivity and high HI titers with homologous strains, compared with protectivity ranging from 40–100% and lower HI titers with heterologous strains resulting from polymorphisms at antigenic sites. Our findings provide valuable insight into the molecular evolution of AIV and have important implications for vaccine efficacy and future vaccination strategies.

      PubDate: 2016-02-27T17:59:29Z
  • Characterization of surface antigen protein 1 (SurA1) from Acinetobacter
           baumannii and its role in virulence and fitness
    • Abstract: Publication date: Available online 26 February 2016
      Source:Veterinary Microbiology
      Author(s): Dong Liu, Zeng-Shan Liu, Pan Hu, Ling Cai, Bao-Quan Fu, Yan-Song Li, Shi-Ying Lu, Nan-Nan Liu, Xiao-Long Ma, Dan Chi, Jiang Chang, Yi-Ming Shui, Zhao-Hui Li, Waqas Ahmad, Yu Zhou, Hong-Lin Ren
      Acinetobacter baumannii is a Gram-negative bacillus that causes nosocomial infections, such as bacteremia, pneumonia, and meningitis and urinary tract and wound infections. In the present study, the surface antigen protein 1 (SurA1) gene of A. baumannii strain CCGGD201101 was identified, cloned and expressed, and then its roles in fitness and virulence were investigated. Virulence was observed in the human lung cancer cell lines A549 and HEp–2at one week after treatment with recombinant SurA1. One isogenic SurA1 knock-out strain, GR0015, which was derived from the A. baumannii strain CCGGD201101 isolated from diseased chicks in a previous study, highlighted the effect of SurA1 on fitness and growth. Its growth rate in LB broth and killing activity in human sera were significantly decreased compared with strain CCGGD201101. In the Galleria mellonella insect model, the isogenic SurA1 knock-out strain exhibited a lower survival rate and decreased dissemination. These results suggest that SurA1 plays an important role in the fitness and virulence of A. baumannii.

      PubDate: 2016-02-27T17:59:29Z
  • Expression of IL-1β, IL-2, IL-10, TNF-β and GM-CSF in peripheral
           blood leukocytes of rabbits experimentally infected with rabbit
           haemorrhagic disease virus
    • Abstract: Publication date: Available online 26 February 2016
      Source:Veterinary Microbiology
      Author(s): Alicja Trzeciak-Ryczek, Beata Tokarz-Deptuła, Wiesław Deptuła
      Rabbit haemorrhagic disease (RHD) is a highly morbid and mortal viral infection of European rabbits. This disease is one of the main causes of death in wild rabbits, and results in large economic losses in farms of rabbits worldwide. Although the first outbreak of this disease was noted in 1984, the pathogenesis of RHD and mechanisms of RHDV (rabbit haemorrhagic disease virus) pathogenecity have still not been fully elucidated. Recent studies indicate a role of the immune response, especially peripheral blood leukocytes (PBL), in the pathogenesis of this disease. Thus, in the present study we investigated the expression of IL-1β, IL-2, IL-10, TNF-β and GM-CSF genes in PBL of RHDV-infected rabbits. We also compared the expression of genes encoding these cytokines in rabbits with different course of RHDV infection (in animals that died 36h postinfection or survived until 60th h after infection). The study revealed that three (IL-10, TNF-β and GM-CSF) out of five investigated genes encoding cytokines showed increased expression in PBL of RHDV-infected rabbits, and the level of expression depended on the course of RHD. The results indicate the potential role of these cytokines in RHDV infection and their influence on the survival time of infected rabbits.

      PubDate: 2016-02-27T17:59:29Z
  • Brucella ovis PA mutants for outer membrane proteins Omp10, Omp19, SP41,
    • Abstract: Publication date: Available online 20 February 2016
      Source:Veterinary Microbiology
      Author(s): Rebeca S. Sidhu-Muñoz, Pilar Sancho, Nieves Vizcaíno
      Mutants in several genes have been obtained on the genetic background of virulent rough (lacking O-polysaccharide) Brucella ovis PA. The target genes encode outer membrane proteins previously associated with the virulence of smooth (bearing O-polysaccharide chains in the lipopolysaccharide) Brucella strains. Multiple attempts to delete omp16, coding for a homologue to peptidoglycan-associated lipoproteins, were unsuccessful, which suggests that Omp16 is probably essential for in vitro survival of B. ovis PA. Single deletion of omp10 or omp19 −that encode two other outer membrane lipoproteins- was achieved, but the simultaneous removal of both genes failed, suggesting a essential complementary function between both proteins. Two other deletion mutants, defective in the Tol-C-homologue BepC or in the SP41 adhesin, were also obtained. Surprisingly when compared to previous results obtained with smooth Brucella, none of the B. ovis mutants showed attenuation in the virulence, either in the mouse model or in cellular models of professional and non-professional phagocytes. Additionally, and in contrast to the observations reported with smooth Brucella strains, several properties related to the outer membrane remained almost unaltered. These results evidence new distinctive traits between naturally rough B. ovis and smooth brucellae.

      PubDate: 2016-02-23T17:51:08Z
  • Genetic &amp; Virulence Profiling of ESBL-positive E. coli from
           Nosocomial &amp; Veterinary Sources
    • Abstract: Publication date: Available online 18 February 2016
      Source:Veterinary Microbiology
      Author(s): JM Tyrrell, M Wootton, MA Toleman, RA Howe, M Woodward, TR Walsh
      CTX-M genes are the most prevalent ESBL globally, infiltrating nosocomial, community and environmental settings. Wild and domesticated animals may act as effective vectors for the dissemination of CTX-producing Enterobacteriaceae. This study aimed to contextualise bla CTX-M-14-positive, cephalosporin-resistant Enterobacteriaceae human infections and compared resistance and pathogenicity markers with veterinary isolates. Epidemiologically related human (n=18) and veterinary (n=4) bla CTX-M-14-positive E. coli were fully characterised. All were typed by XbaI pulsed field gel electrophoresis and ST. Chromosomal/plasmidic locations of bla CTX-M-14 were deduced by S1-nuclease digestion, and association with ISEcp1 was investigated by sequencing. Conjugation experiments assessed transmissibility of plasmids carrying bla CTX-M-14. Presence of virulence determinants was screened by PCR assay and pathogenicity potential was determined by in vitro Galleria mellonella infection models. 84% of clinical E. coli originated from community patients. bla CTX-M-14 was found ubiquitously downstream of ISEcp1 upon conjugative plasmids (25–150kb). bla CTX-M-14 was also found upon the chromosome of eight E. coli isolates. CTX-M-14-producing E. coli were found at multiple hospital sites. Clonal commonality between patient, hospitals and livestock microbial populations was found. In vivo model survival rates from clinical isolates (30%) and veterinary isolates (0%) were significantly different (p<0.05). Co-transfer of bla CTX-M-14 and virulence determinants was demonstrated. There is evidence of clonal spread of bla CTX-M-14-positive E. coli involving community patients and farm livestock. bla CTX-M-14 positive human clinical isolates carry a lower intrinsic pathogenic potential than veterinary E. coli highlighting the need for greater veterinary practices in preventing dissemination of MDR E. coli among livestock.

      PubDate: 2016-02-23T17:51:08Z
  • Disruption of the sigS gene attenuates the local innate immune response to
           Staphylococcus aureus in a mouse mastitis model
    • Abstract: Publication date: Available online 20 February 2016
      Source:Veterinary Microbiology
      Author(s): Vincent Peton, Koen Breyne, Lucie Rault, Kristel Demeyere, Nadia Berkova, Evelyne Meyer, Sergine Even, Yves Le Loir
      Staphylococcus aureus (S. aureus) is a major pathogen involved in ruminant mastitis and present worldwide. Clinical signs of S. aureus mastitis vary considerably and are largely dependent on strain-specific factors. A comparison of two S. aureus strains that reproducibly induced either severe (O11) or mild (O46) mastitis in ewes revealed that the transcriptional regulator sigS was mutated in O46 (Le Maréchal et al., 2011. PLoS One 6 (11): e27354. doi:10.1371/journal.pone.0027354). In the present paper, we analysed the sigS sequence in 18 other S. aureus strains isolated from goat or ewe mastitis and found a 4-bp deletion similar to that of the O46 sigS gene in three strains associated with subclinical ewe mastitis. This sigS gene was disrupted in strain O11 (O11ΔsigS), so our aim was to investigate its involvement in the severity of infections in the context of mastitis. The wild type (wt) and mutant strains were then characterized in vitro to determine the involvement of sigS in the response to S. aureus under various stress conditions, and assess its influence on the cytotoxicity of the pathogen, its invasive capacity and biofilm formation. The strains were compared in vivo in an experimental mouse mastitis model in which clinical signs and cytokine production were evaluated at 24hours post-infection. While no significant differences in the effect on bacterial growth between O11 and O11ΔsigS were observed either in vitro or in vivo, a significantly weaker in vivo production of interleukin (IL)-1α, IL-1β, and Tumor Necrosis Factor (TNF)-α was measured in the mammary glands infected with the mutant strain, suggesting that infection with O11ΔsigS induced an attenuated local innate immune response. These results suggest an impact of sigS disruption on S. aureus pathogenesis in a ruminant mastitis context. This disruption is probably involved in, and may partly explain, the milder symptoms previously observed in S. aureus O46-induced mastitis in ewes.

      PubDate: 2016-02-23T17:51:08Z
  • Mycoplasma bovis isolates recovered from cattle and bison (Bison bison)
           show differential in vitro effects on PBMC proliferation, alveolar
           macrophage apoptosis and invasion of epithelial and immune cells
    • Abstract: Publication date: Available online 23 February 2016
      Source:Veterinary Microbiology
      Author(s): Muhammad Suleman, Tracy Prysliak, Kyle Clarke, Pat Burrage, Claire Windeyer, Jose Perez-Casal
      In the last few years, several outbreaks of pneumonia, systemically disseminated infection, and high mortality associated with Mycoplasma bovis (M. bovis) in North American bison (Bison bison) have been reported in Alberta, Manitoba, Saskatchewan, Nebraska, New Mexico, Montana, North Dakota, and Kansas. M. bovis causes Chronic Pneumonia and Polyarthritis Syndrome (CPPS) in young, stressed calves in intensively-managed feedlots. M. bovis is not classified as a primary pathogen in cattle, but in bison it appears to be a primary causative agent with rapid progression of disease with fatal outcomes and an average 20% mature herd mortality. Thus, there is a possibility that M. bovis isolates from cattle and bison differ in their pathogenicity. Hence, we decided to compare selected cattle isolates to several bison isolates obtained from clinical cases. We show differences in modulation of PBMC proliferation, invasion of trachea and lung epithelial cells, along with modulation of apoptosis and survival in alveolar macrophages. We concluded that some bison isolates showed less inhibition of cattle and bison PBMC proliferation, were not able to suppress alveolar macrophage apoptosis as efficiently as cattle isolates, and were more or less invasive than the cattle isolate in various cells. These findings provide evidence about the differential properties of M. bovis isolated from the two species and has helped in the selection of bison isolates for genomic sequencing.

      PubDate: 2016-02-23T17:51:08Z
  • Chondroitinase AC: A host-associated genetic feature of Helicobacter
    • Abstract: Publication date: Available online 23 February 2016
      Source:Veterinary Microbiology
      Author(s): Namburi Ramesh Babu, Berteau Olivier, Spillmann Dorothe, Mirko Rossi
      Investigating mechanisms involved in host adaptation is crucial to understand pathogen evolution. Helicobacter species appear to have a host species-specific tropism, coevolving with their natural hosts, and to develop several strategies allowing the colonization of the stomach throughout lifetime of their hosts. However, little is known about genetic features associated with the adaptation to a specific animal host. In this study we discovered a polysaccharide lyase that is expressed by the canine-associated species H. bizzozeronii and acts as chondroitinase AC-type lyase of broad specificity. Except for its low pH-optimum between pH 4.0 and pH 5.5, the properties of the H. bizzozeronii chondroitin lyase AC resemble the ones from Arthrobacter aurescens. However, homologues of this gene have been detected only in Helicobacter species colonizing the canine and feline gastric mucosa. Since a unique feature of the canine stomach is the secretion of chondroitin-4-sulphate in the gastric juice of the fundus mucosa by chief cells, the expression of chondroitinase AC by H. bizzozeronii is likely the consequence of adaptation of this bacterium to its host and a potential link to gastric disorders in dogs.

      PubDate: 2016-02-23T17:51:08Z
  • Detailed molecular analyses of the hexon loop-1 and fibers of fowl
           aviadenoviruses reveal new insights into the antigenic relationship and
           confirm that specific genotypes are involved in field outbreaks of
           inclusion body hepatitis
    • Abstract: Publication date: Available online 15 February 2016
      Source:Veterinary Microbiology
      Author(s): Anna Schachner, Ana Marek, Beatrice Grafl, Michael Hess
      Forty-eight fowl aviadenoviruses (FAdVs) isolated from recent IBH outbreaks across Europe were investigated, by utilizing for the first time the two major adenoviral antigenic domains, hexon loop-1 and fiber, for compound molecular characterization of IBH-associated FAdVs. Successful target gene amplification, following virus isolation in cell culture or from FTA-card samples, demonstrated presence of FAdVs in all cases indicative for IBH. Based on hexon loop-1 analysis, 31 European field isolates exhibited highest nucleotide identity (>97.2%) to reference strains FAdV-2 or −11 representing FAdV-D, while 16 and one European isolates shared>96.0% nucleotide identity with FAdV-8a and −8b, or FAdV-7, the prototype strains representing FAdV-E. These results extend recognition of specific FAdV-D and FAdV-E affiliate genotypes as causative agents of IBH to the European continent. In all isolates, species specificity determined by fiber gene analysis correlated with hexon-based typing. A threshold of 72.0% intraspecies nucleotide identity between fibers from investigated prototype and field strains corresponded with demarcation criteria proposed for hexon, suggesting fiber-based analysis as a complementary tool for molecular FAdV typing. A limited number of strains exhibited inconsistencies between hexon and fiber subclustering, indicating potential constraints for single-gene based typing of those FAdVs. Within FAdV-D, field isolate fibers shared a high degree of nucleotide (>96.7%) and aa (>95.8%) identity, while FAdV-E field isolate fibers displayed greater nucleotide divergence of up to 22.6%, resulting in lower aa identities of>81.7%. Furthermore, comparison with FAdVs from IBH outbreaks outside Europe revealed close genetic relationship in the fiber, independent of the strainś geographic origin.

      PubDate: 2016-02-18T17:38:22Z
  • Rapid dissemination of M. bovis from cattle dung to soil by the earthworm
           Lumbricus terrestris
    • Abstract: Publication date: Available online 16 February 2016
      Source:Veterinary Microbiology
      Author(s): Elodie Barbier, Benoit Chantemesse, Murielle Rochelet, Léon Fayolle, Loïc Bollache, Maria Laura Boschiroli, Alan Hartmann
      Indirect transmission of Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), between wildlife and livestock is thought to occur by inhalation or ingestion of environmental substrates contaminated through animal shedding. The role of the soil fauna, such as earthworms, in the circulation of M. bovis from contaminated animal feces is of interest in the epidemiology of bTB. The objective of this study was to assess the impact of earthworm activity on M. bovis transfer from animal dung to castings and the surrounding soil. For this purpose, microcosms of soil containing the anecic eathworms Lumbricus terrestris were prepared and covered with cattle feces spiked with the M. bovis BCG strain Pasteur to carry out two separate experiments. The dissemination, the gut carriage and the excretion of M. bovis were all monitored using a specific qPCR-based assay. Our results showed that the earthworm L. terrestris was able to rapidly disseminate M. bovis from the contaminated cattle feces to the surrounding soil through casting egestion. Moreover, contaminated earthworms were shown to shed the bacteria for 4days when transferred to a M. bovis-free soil. This study highlights for the first time the possible role of earthworms in the dissemination and the persistence of M. bovis in soils in bTB endemic areas.

      PubDate: 2016-02-18T17:38:22Z
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